He first appeared in Series 41 in 1999 where he won his first game against Billy Davidson. He then won his second game against Julie Smithies before bowing out in a defeat to Rob Watson. Manwani returned to the programme 19 years later in 2018 during Series 79 and won all 8 heat games, becoming the second octochamp of the series, following Adam Rolston completing his run before Manwani.

Manwani's total of 715 points placed him in the #1 spot on the Series 79 leaderboard at the time he completed his octorun. As a result of his successes, he has now garnered a place in the series finals in December 2018.